what is the correct tyre pressure for everyday use?
- Thread starter Z4MMM
- Start date
Oh come on! Please.
As epbrown said,
"Yes, they set mine to 35psi after the 1200-mile break-in service, and the car was worse than when I had run-flats on my roadster. I'm running at 30psi front and 32psi rear right now. The fronts have to be 30psi for decent ride quality. I'm still fiddling with the rear pressures to see what I like in terms of grip and ride quality."
This has been my exact experience. The door plate calls for 30/30 psi, but the M Coupe supplementary manual calls for 30/32, which I find ideal. My shop wanted me to try 35/35, and I found that inflation to be amazingly harsh given it was not all that great a change.
EB
"Yes, they set mine to 35psi after the 1200-mile break-in service, and the car was worse than when I had run-flats on my roadster. I'm running at 30psi front and 32psi rear right now. The fronts have to be 30psi for decent ride quality. I'm still fiddling with the rear pressures to see what I like in terms of grip and ride quality."
This has been my exact experience. The door plate calls for 30/30 psi, but the M Coupe supplementary manual calls for 30/32, which I find ideal. My shop wanted me to try 35/35, and I found that inflation to be amazingly harsh given it was not all that great a change.
EB
I would guess it was directed at me. Nevertheless this is an issue which has been recognised by others more knowledgeable than myself. It's not rocket science, look at the close proximity of the exhaust to the tyres or even stick your hand behind the wheel after a bit of spirited driving. The heat does transfer to the tyres quickly and will obviously increase the pressure. It's easy to put a couple of pounds of pressure into the tyres in normal driving so what I'm saying is if you drive the car quickly then by starting out at 29psi, the tyres will soon reach 31/32psi and beyond. Makes sense to me and IMO the pressures I'm running with work very well and validate my opinion. If you think it's a ridiculous premise so be it but at least give an explanation why.
epbrown said:
Genius!
How did you know?
takedown8 said:
Just checked the door. 33psi front, 36psi rear also. I have the 3.0I with 18's and the sport package. Thats how I run them, exhaust be damned, although the point is well taken. There are so many variables, Vehicle type, tire size, etc.... and personal preference. If your within a couple of pounds I see no problem. I'm running Michelin PS2's and they have a max inflation of 45 psi, a good safety factor.
This has been an interesting thread to me - I am not in a ///M but I am also not running RFTs and have the same tire size as the ///M. I have been playing around with tire pressures and have not been happy with my 18" wheels at all while trying to be even moderately faithful to the numbers in my manual and on the door frame (33F/38R). I run 17" winter wheels at around 34psi on all 4 wheels and that seems to be a reasonable ride with pretty uniform tire wear so far.
On the track with my 18" wheels and Michelin PS2s I have finally settled in on 32psi F/R (hot) for dry conditions and like the feel for the traction I get out of that. Anything higher gets pretty greasy by late in the lapping session.
Yesterday I had a student at an HPDE with a ///M Z4 roadster and while I was coaching him to get his own tires down to that number (someone told him he needed 36-38 for track) he mentioned that 31-32 was the recommended number on his door frame and in his manual as well. I decided to try out that pressure for my 18's when I got home and interestingly enough the car feels almost identical to his ///M which is a lot nicer than anything even 2-3psi higher I have tried so far. This seems to match pretty closely what I have read here so far and suggests that those of us with non ///Ms who leave the RFT fold need to be looking at the ///M manual for useful guidance on how to inflate our tires........
:smart:
On the track with my 18" wheels and Michelin PS2s I have finally settled in on 32psi F/R (hot) for dry conditions and like the feel for the traction I get out of that. Anything higher gets pretty greasy by late in the lapping session.
Yesterday I had a student at an HPDE with a ///M Z4 roadster and while I was coaching him to get his own tires down to that number (someone told him he needed 36-38 for track) he mentioned that 31-32 was the recommended number on his door frame and in his manual as well. I decided to try out that pressure for my 18's when I got home and interestingly enough the car feels almost identical to his ///M which is a lot nicer than anything even 2-3psi higher I have tried so far. This seems to match pretty closely what I have read here so far and suggests that those of us with non ///Ms who leave the RFT fold need to be looking at the ///M manual for useful guidance on how to inflate our tires........
:smart:
So... I've had the tyres at 32 psi f&r for about 2 - 3 weeks now, and it just hasn't felt quite right to me, despite it being the "correct" pressure. I've now dropped the front to 28, and it feels near perfect! Might try dropping the rear to 30 too, just to see how that feels, but dropping the front has made the car feel much more stable when cornering at speed. :driving:
There's a trick we use on the 4x4's to work out correct pressure as nothing on them is standard in terms of rim size, tyre size, weight, front rear distribution, suspension set up, etc. etc.
Take the car to a nice flat car park with some smooth tarmac on it. Draw a thick line of chalk side to side across the tread and dive forward in a dead straight line for 100m or so. Check the tyre. If the chalks worn evenly spot on. Centre only worn = way too high, outer worn = way too low.
Not suggesting for 1 minute that you rely on this in isolation, but it's a good indicator of if your in the zone, especially on wide tyres that are more pressure sensitive.
Take the car to a nice flat car park with some smooth tarmac on it. Draw a thick line of chalk side to side across the tread and dive forward in a dead straight line for 100m or so. Check the tyre. If the chalks worn evenly spot on. Centre only worn = way too high, outer worn = way too low.
Not suggesting for 1 minute that you rely on this in isolation, but it's a good indicator of if your in the zone, especially on wide tyres that are more pressure sensitive.
I had the tyre warning light come on the other day whilst on the motorway.
Pulled over into services and rang BMW assistance about what to do and what the correct pressures should be.
They said fronts should be 32 and rears 36, so pumped them up to that.
Today I have looked at the sticker on the door sill and it states 2.1 and 2.2 bar which is about 31 / 32 psi.
Current have the fronts at 32 and rears at 36. Think I may call the garage tomorrow to see what the actual pressure should be.
Pulled over into services and rang BMW assistance about what to do and what the correct pressures should be.
They said fronts should be 32 and rears 36, so pumped them up to that.
Today I have looked at the sticker on the door sill and it states 2.1 and 2.2 bar which is about 31 / 32 psi.
Current have the fronts at 32 and rears at 36. Think I may call the garage tomorrow to see what the actual pressure should be.
A
Anonymous
Guest
30 front and rear on the door post of my M Roadster - always been good for me.
Go for exactly what it says on the door or handbook unless you have 1) changed the size of the tyre or 2) experimentaion has shown you a slightly higher or lower pressure suits your type and style of driving.
Generally garages are useless and overpressure and at best refer to a wallchart and oft use poorly set gauges.
Generally garages are useless and overpressure and at best refer to a wallchart and oft use poorly set gauges.
I agree with DGM on this one. The pressures quoted by BMW may suit the standard wheel/Conti set-up but CSL wheels definately need lower prssures to get a good mix of ride quality and handling. My tyres increase on pressure by 6psi after 15 monutes of track day work so I've chosen to set them at 29 front and 31 rear. The fronts must be softer or the steering becomes skittery (is that a Scottish word?) and the car tramlines more.
I reckon you should throw out the rule book and play about a little to find a setting that suits you. If you're into fast road/track or live somewhere hot then i'd look at the softer pressures.
Phew.
Sixspeed - did you check your pressures at the Nurburgring after a lap? Mine went up considerably and I found myself reducing pressure between laps otherwise i'd have ended up with 40psi ?
I reckon you should throw out the rule book and play about a little to find a setting that suits you. If you're into fast road/track or live somewhere hot then i'd look at the softer pressures.
Phew.
Sixspeed - did you check your pressures at the Nurburgring after a lap? Mine went up considerably and I found myself reducing pressure between laps otherwise i'd have ended up with 40psi ?
Sorry guys but how the hell can we have a thread 3 pages long about tyre frickin' pressures! :headbang:
